Flexible displays are the new must-have element in the race for the next generation of high-tech electronic devices. A new prototype display created with graphene promises to provide a more efficient, printable alternative to current construction methods with the added benefit of perhaps one day creating a true, fully-folding display.
Created as an active matrix electrophoretic (the technique of using an electric field to create images by rearranging particles suspended in a solution) display, the prototype produced by the University of Cambridge Graphene Centre and UK firm Plastic Logic, is similar to the screens used in e-readers. However, instead of being composed of sheets of glass, it is created using screens of flexible plastic and is the first time graphene has been used in a transistor-based flexible device.
In a further difference to conventional displays, the backplane (the common electrical connection layer which supplies power, in this case, to rearrange the suspended display particles) incorporates an emulsion-processed graphene electrode, instead of the standard sputter-deposited metal electrode layer. In other words, the backplane layer can be produced using a low-temperature process in which the graphene is essentially "printed" onto the substrate.
In this instance, the 150 pixel per inch backplane created was produced at temperatures of less than 100° C (212° F) using Organic Thin Film Transistor technology developed by Plastic Logic. The subsequently deposited electrode was then etched with the required circuit patterns to provide the network of backplane connections.
Though flexible screens are already appearing in electronic devices today, such as those produced by manufacturers like LG, this new graphene-based display is the first to realize the use of what is rapidly becoming a low-cost, high-volume solution in electronics.
With its inherent electrical properties exploitable in everything from conductors, through to supercapacitors, solar cells and a myriad other electronic components composed entirely of manipulated graphene, a flexible display constructed from this material may well provide the least expensive, easiest to manufacture solution yet.
Projected future developments may also include LCD and OLED technologies to provide full color capabilities and support for high-speed refresh rates required for displaying video. The team also envisages the new flexible backplanes may be lightweight and malleable enough to be used as high-density sensors for use in such things as high-resolution medical imaging systems or super-accurate gesture recognition applications.
"We are happy to see our collaboration with Plastic Logic resulting in the first graphene-based electrophoretic display exploiting graphene in its pixels’ electronics," said the Director of the Cambridge Graphene Centre, Professor Andrea Ferrari. "This is a significant step forward to enable fully wearable and flexible devices. This cements the Cambridge graphene-technology cluster and shows how an effective academic-industrial partnership is key to help move graphene from the lab to the factory floor."
This research was recently aided by a grant from the UK Technology Strategy Board, as part of the "Realizing the graphene revolution" initiative, and will be used to attempt to produce a full-color, OLED-based flexible graphene display within the next year.
The video below, produced by the Plastic Logic team, shows the new flexible prototype display in use.
Source: University of Cambridge
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